This is the 'possessed' variant, the first release, which was mass produced and so you can get him on eBay for a few pounds. In a quick two minute search on eBay (cough cough, hint hint), I found the cheapest is £3.99.

Whereas the 'unpossessed' variant without markings is slightly rarer as it was part of the Woolworths exclusive wave. However, looking on eBay, it isn't all that expensive, a mere £12.99 which isn't so bad.